YORK, Britain, Dec. 6 (Xinhua) -- China's world number eight Ding Junhui suffered a surprise 6-4 defeat to Englishman Martin O'Donnell in the round of 16 at the UK Snooker Championship here on Thursday.

Former world number one Ding, who won the event at 2005 and 2009, gave the world number 59 the first victory in this tournament after five failed attempts.

Ding led 3-2 but slipped in the next three frames to go 3-5 behind. He pulled one back and had a scoring chance in frame 10 but ran out of position on 21 and played safe. O'Donnell knocked in an excellent long red to initiate a match-winning run of 41.

"I have more chances today but I did not take them," Ding said. "I played very badly. "

Ding said that the poor air conditioning in York's Barbican Centre has affected his performance.

"I had to guess where the ball should go," he said of the wind from the air conditioners. "It's too difficult."

O'Donnell described the match as "the biggest win of his career." Ding said that he has made too many mistakes.

"He didn't play well in the middle of the match, but I just gave him too many chances, which made him more and more confident."

"I am just not good enough today," he said.

O'Donnell has secured at least 22,500 pounds of prize money and a mouth-watering quarterfinal showdown against defending champion Ronnie O'Sullivan on Friday.

"I'm not here just to get to quarterfinals so I haven't achieved anything yet,"said O'Donnell, who has beaten four Chinese players in this event.

"I'll relax tonight and get ready for tomorrow. Ronnie is the greatest player ever and it will be a privilege to play him. I'll just keep doing what I'm doing and take the game to him. I practise six or seven hours a day believing that when I get my chance I'll be able to take it.

"He could beat me 6-0 and it has still been a good tournament for me."

Judd Trump, a former champion, was also knocked out, losing 6-4 to Joe Perry. Enditem